[ARC5] Carbon mic replacements

[Jim Haynes]

Thanks for that circuit.

There was a discussion in Electric Radio some time back about the electret
elements.  Many of them are wide frequency range.  Some are specialized 
for speech communication frequency range.  The article mentioned, as I
recall, some you can get from Mouser.

For the person who asked about the electret being an open circuit - the
capsule you get includes an amplifier built in, so that's why the mic
needs voltage to make it operate.